690 INDEX Electrodynamics of moving media (cont.) 131, 132n, 253. See also Ponderomotive force Electromagnetic waves, energy of: Josef Weiß on, 163-165 Electrometer, AE's construction of, 150 Electron: deformable: and superluminal velocity, 57, Wilhelm Wien's support of, 57 in magnetic field, AE on invalidity of mechanics for, 359 mass of, AE's com- ments on nature of, 88 motion of in electromagnetic field, Arthur Schuster's calculation of, 138n new theory of, AE's comments on need for, 88 rest energy of, AE's comments on, 88 rigid, and superlu- minal velocity, 57, 58, 65 Electron, specific charge of: determination of, 114, 115n, 186 Alfred Bucherer's determination of, 133-134, 135n, 136-138 Erich Hupka's determination of, 187n, 189 Walter Kaufmann's determina- tion of: 138, Alfred Bucherer's criticism of, 136, 137, 139, disagreement with spe- cial relativity of, 78n, Max Planck's criticism of, 77 discussion between Walter Kaufmann and Max Planck on, 79n Johannes Classen's value for, 138n Electron theory: AE's work on, 11 of metals: Michele Besso on, 318, 342, Paul Drude's results in, 320n, Paul Gruner's work on, 145-147, 147n superluminal velocity in, 56 Electron theory, Lorentz's, and Walter Kaufmann's experiments, 138 Electrophorus, invention of, 51 Electrostatics: use of electrophorus in, 51 use of friction machines in, 51 use of induction machines in, 51 Elster, Julius (1854-1920), 384n induction machine of, 52 Energetics, AE's comments on, 285 Energy: in Maxwell theory: AE on, 229, 230n, AE's expression for, 225-226 in quantum theory, AE on, 228-229 of elec- tromagnetic waves, Josef Weiß on, 163-165 of X-rays, Arnold Sommerfeld's paper on spatial distribution of, 228 Energy, law of conservation of: AE on possi- ble statistical validity of, 261n AE's renunciation of in radiation theory, 261 AE's use of, 10, 17 in AE's and Marcel Grossmann's theory of gravitation, 552 Enke publishing firm, 430n Enke, Alfred (1852-1937), 430, 430n Ensemble, canonical: H. A. Lorentz's use of in deriving Planck's law, 172-173 Ensemble, microcanonical: equations of motion for, 18n Entropy: addition theorem of, validity for radiation of, 42n AE's derivation of, 10 behavior for infinite pressure, Michael Polanyi on, 514 calculation of, AE on problems of, 310, 321 for non-equilib- rium states, AE on, 310 Ludwig Boltzmann's interpretation of, 87 of radi- ation: AE on volume dependence of, 210, Max Laue on, 83, Max Planck on, 49 of universe: Aurel Stodola on, 125, Svante Arrhenius on, 125 relation with probabil- ity, AE on, 188n Eötvös, Roland von (1848-1919), experi- ments on equality of gravitational and inertial mass: AE's ignorance of, 498n Eötvös's law, AE's paper on, 401n Richard Swinne's comments on, 401 Epstein, Paul (1883-1966), 567n Equation of state: for moderately compressed gases, derived by Hans Tanner, 334n for solids, 415 Equivalence of mass and energy: AE's dis- covery of, 33 Alfred Bucherer on, 147 experimental test of, 33 in AE's and Marcel Grossmann's theory of gravita- tion, 588, 604 in electrodynamics, Alfred Bucherer and Max Planck on, 148 Equivalence principle, 466n, 531 conse- quences of, 86n Max Laue's criticism of, 384 validity in AE's theory of static grav- itational field, 486 Ernst, Heinrich (1847-1934), 215n, 274n letter from Schinz, Hans, 291n letter from Stoll, Otto, 190n letter from Zangger, Heinrich, 596n Ernst, Otto (1862-1926), 518n ETH: AE's studies at, 4, 34 AE's succession at, 595 change of title of, 332n curricu- lum at: AE's view on, 351, Marcel Grossmann's view on, 351 establishment of theoretical physics chair at, objections to, 33n, 340n, 350n expansion of, 366n,